TNF-alpha in cancer treatment: molecular insights, antitumor effects, and clinical utility

Inhibition of cell growth and potentiation of tumor necrosis factor-α (TNF-α)-induced apoptosis by a phenanthroindolizidine alkaloid antofine in human colon cancer cells

Based on the potential of natural products as a source for the development of cancer chemotherapeutic agents, this study was performed to investigate the anti-proliferative and antitumor effects of antofine, a phenanthroindolizidine alkaloid derived from Cynanchum paniculatum. Antofine showed potent anti-proliferative effects in several human cancer cells with IC(50) values in the nanomolar range. Treatment with antofine for 24h did not result in the induction of apoptotic cell death but moderately induced cell cycle arrest at G0/G1 phase and inhibited the expression of cyclin D1, cyclin E, and CDK4. In addition, antofine inhibited the transcriptional activity of β-catenin/Tcf in human colon HCT 116 cells, and the expression level of β-catenin and cyclin D1 was also down-regulated by antofine in human colon SW480 cells. Moreover, antofine potentiated tumor necrosis factor-α (TNF-α)-induced apoptosis, which was demonstrated by the increase of Annexin V-positive cell population and of the cleavage of poly (ADP-ribose) polymerase (PARP) and caspase-8. Antofine also effectively suppressed tumor growth in the HCT 116 implanted xenograft nude mouse model. Taken together, these findings suggest that antofine might be a potential candidate for the development of cancer chemotherapeutic agents derived from natural products.

Activated CD4+ T cells enhance radiation effect through the cooperation of interferon-gamma and TNF-alpha

Background

Approaches that enhance radiation effect may lead to improved clinical outcome and decrease toxicity. Here we investigated whether activated CD4+ T cells (aCD4) can serve as an effective radiosensitizer.

Methods

CD4+ T cells were activated with anti-CD3 and anti-CD28 mAbs. Hela cells were presensitized with aCD4 or conditioned supernatant (aCD4S) or recombinant cytokines for 2 days, followed γ-irradiation. The treated cells were cultured for an additional 2 to 5 days for cell proliferation, cell cycle, and western blot assays. For confirmation, other cancer cell lines were also used.

Results

Presensitization of tumor cells with aCD4 greatly increased tumor cell growth inhibition. Soluble factors secreted from activated CD4⁺ T cells were primarily responsible for the observed effect. IFN-γ seemed to play a major role. TNF-α, though inactive by itself, significantly augmented the radiosensitizing activity of IFN-γ. aCD4S, but not IFN-γ or IFN-γ/TNF-α combination, was found to enhance the γ-irradiation-induced G2/M phase arrest. Bax expression was highly upregulated in Hela cells presensitized with aCD4S followed by γ-irradiation. The radio-sensitizing activity of aCD4 is not uniquely observed with Hela cell line, but also seen with other cancer cell lines of various histology.

Conclusions

Our findings suggest possible molecular and cellular mechanisms that may help explain the radio-sensitization effect of activated lymphocytes, and may provide an improved strategy in the treatment of cancer with radiotherapy.

Ion channels and the hallmarks of cancer

Plasma membrane (PM) ion channels contribute to virtually all basic cellular processes and are also involved in the malignant phenotype of cancer cells. Here, we review the role of ion channels in cancer in the context of their involvement in the defined hallmarks of cancer: 1) self-sufficiency in growth signals, 2) insensitivity to antigrowth signals, 3) evasion of programmed cell death (apoptosis), 4) limitless replicative potential, 5) sustained angiogenesis and 6) tissue invasion and metastasis. Recent studies have indicated that the contribution of specific ion channels to these hallmarks varies for different types of cancer. Therefore, to determine the importance of ion channels as targets for cancer diagnosis and treatment their expression, function and regulation must be assessed for each cancer.

Cancer risk in patients with rheumatoid arthritis treated with anti-tumor necrosis factor alpha therapies: does the risk change with the time since start of treatment?

OBJECTIVE

To determine the short-term and medium-term risks of cancer in patients receiving anti-tumor necrosis factor alpha (anti-TNFalpha) therapies that have proven effective in the treatment of chronic inflammatory conditions.

METHODS

By linking together data from the Swedish Biologics Register, Swedish registers of RA, and the Swedish Cancer Register, we identified and analyzed for cancer occurrence a national cohort of 6,366 patients with RA who first started anti-TNF therapy between January 1999 and July 2006. As comparators, we used a national biologics-naive RA cohort (n = 61,160), a cohort of RA patients newly starting methotrexate (n = 5,989), a cohort of RA patients newly starting disease-modifying antirheumatic drug combination therapy (n = 1,838), and the general population of Sweden. Relative risks (RRs) were estimated using Cox regression analyses, examining overall RR as well as RR by time since the first start of anti-TNF therapy, by the duration of active anti-TNF therapy, and by the anti-TNF agent received.

RESULTS

During 25,693 person-years of followup in 6,366 patients newly starting anti-TNF, 240 first cancers occurred, yielding an RR of 1.00 (95% confidence interval 0.86-1.15) versus the biologics-naive RA cohort, and similar RRs versus the other 2 RA comparators. RRs did not increase with increasing time since the start of anti-TNF therapy, nor with the cumulative duration of active anti-TNF therapy. During the first year following the first treatment start, but not thereafter, dissimilar cancer risks for adalimumab, etanercept, and infliximab were observed.

CONCLUSION

During the first 6 years after the start of anti-TNF therapy in routine care, no overall elevation of cancer risk and no increase with followup time were observed.

Changes in cytokine and biomarker blood levels in patients with colorectal cancer during dendritic cell-based vaccination

INTRODUCTION. Immunotherapy based on dendritic cell vaccination has exciting perspectives for treatment of cancer. In order to clarify immunological mechanisms during vaccination it is essential with intensive monitoring of the responses. This may lead to optimization of treatment and prediction of responding patients. The aim of this study was to evaluate cytokine and biomarker responses in patients with colorectal cancer treated with a cancer vaccine based on dendritic cells pulsed with an allogeneic melanoma cell lysate. MATERIAL AND METHODS. Plasma and serum samples were collected prior to vaccination and continuously during treatment. GM-CSF, IL-2, IL-6, TNF-alpha, IFN-gamma, IL-4, IL-8, IL-1b, IL-5, IL-10, IL-12, MIP-1b, IP-10 and Eotaxin were analyzed in a multiplex assay with a Luminex 100 instrument. CEA and TIMP-1 were analysed on ELISA platforms. RESULTS. Patients achieving stable disease showed increasing levels of plasma GM-CSF, TNF-alpha, IFN-gamma, IL-2, and IL-5. Patients with progressive disease showed significant increase in CEA and TIMP-1 levels, while patients with stable disease showed relatively unaltered levels. CONCLUSION. The increased levels of key pro-inflammatory cytokines in serum of patients who achieved stable disease following vaccination suggest the occurrence of vaccine-induced Th1 responses. Since Th1 responses seem to be essential in cancer immunotherapy this may indicate a therapeutic potential of the vaccine.

Intratumoral delivery of encapsulated IL-12, IL-18 and TNF-alpha in a model of metastatic breast cancer

Intratumoral (i.t.) cytokine release through the use of poly-lactic acid microspheres (PLAM) holds tremendous potential for the immunotherapy of breast cancer as it harnesses the immunologic potential of autologous tumor in a clinically feasible and minimally toxic manner. We examined the potential of combinations of i.t. IL-12, IL-18 and TNF-alpha PLAM to generate a tumor-specific immune response and improve outcome in a model of metastatic breast cancer. Balb/c mice with established 4T1 mammary carcinomas were treated with a single injection of BSA, IL-12, IL-18 or TNF-alpha-loaded PLAM alone or in combination after spontaneous metastases occurred. Combined treatment with IL-12 and TNF-alpha PLAM was superior to all other treatments, including the triple combination of IL-12, IL-18 and TNF-alpha in ablation of the primary tumor, eradicating distant disease and enhancing survival. Simultaneous delivery of IL-12 and TNF-alpha was superior to sequential delivery of IL-12 followed by TNF-alpha, but not TNF-alpha followed by IL-12. In vivo lymphocyte depletion studies established that the effects of IL-12 alone are mediated primarily by NK cells, while the combination of IL-12 and TNF-alpha is dependent upon CD8+ T-cells. Only the combination of IL-12 and TNF-alpha results in an increase in both CD4+ and CD8+ T-cells and a reduction in CD4+CD25+ cells. While there was no change in the dendritic cell population, IL-12 and TNF-alpha resulted in a dramatic increase in DC maturation and antigen presentation. Neoadjuvant immunotherapy with simultaneous intratumoral delivery of IL-12 and TNF-alpha PLAM augments DC antigen presentation and increases cytotoxic T-cells without increasing regulatory T-cells, resulting in a T-cell based anti-tumor immune response capable of eradicating disseminated disease. The addition of IL-18 did not improve the efficacy.

In vitro performance of an injectable hydrogel/microsphere based immunocyte delivery system for localised anti-tumour activity

The current practice of cell immunotherapy against cancer has encountered a substantial challenge, that is, targeted delivery of therapeutic cells to tumour sites is not favourably managed. In this study, we aimed to provide an engineering solution to govern the cell targeting and actions, for which a biomaterial model is developed to mediate the conveyance and accommodation of activated immunocytes with anti-cancer potentials. We fabricated a dual-layered hydrogel/microsphere (GS) composite, which preserves all advantageous features of hydrogel such as injectability and favourable permeability, to achieve genuine localisation and physical immobilisation of the executing immunocytes-macrophages. According to our presented in vitro investigations, the GS immunoconstruct exhibited effective elimination of carcinoma cells as well as high safety free of gene alteration or cell leakage. Notably, unwanted long-term proliferation of the delivered cells was restrained by physical encapsulation in the bio-inert 3D hydrogel frameworks. By these efforts, we have provided an immunocyte delivery platform with which cell-based immunotherapy can be initiated at a desired location and implemented in a controlled manner.

Tumor necrosis factor deficiency inhibits mammary tumorigenesis and a tumor necrosis factor neutralizing antibody decreases mammary tumor growth in neu/erbB2 transgenic mice

Tumor necrosis factor-alpha (TNF-alpha) is a pleiotropic cytokine that is synthesized and secreted by cells of the immune system, as well as by certain epithelia and stroma. Based on our previous studies demonstrating TNF-stimulated proliferation of normal and malignant mammary epithelial cells, we hypothesized that TNF might promote the growth of breast cancer in vivo. To test this, we generated bigenic mice that overexpressed activated neu/erbB2 in the mammary epithelium and whose TNF status was wild-type, heterozygous, or null. Mammary tumorigenesis was significantly decreased in TNF-/- mice (n = 30) compared with that in TNF+/+ mice (n = 27), with a palpable tumor incidence of 10.0% and 44.4%, and palpable tumors/mouse of 0.10 +/- 0.06 and 0.67 +/- 0.17, respectively. Tumorigenesis in the heterozygous group fell between that in the TNF+/+ and TNF-/- groups, but was not significantly different from either of the homozygous groups. The decreased tumor development in the TNF-/- mice was associated with a decreased proliferative index in the lobular and ductal mammary epithelium. To further investigate the role of TNF in breast cancer, mammary tumor-bearing mice whose tumors overexpressed wild-type neu/erbB2 were treated with a TNF-neutralizing antibody or a control antibody for 4 weeks (n = 20/group). Mammary tumor growth was significantly inhibited in mice treated with the anti-TNF antibody compared with the control antibody. Together, these data show a stimulatory role for TNF in the growth of breast tumors and suggest that TNF antagonists may be effective in a subset of patients with breast cancer.

Lack of TNFalpha expression protects anaplastic lymphoma kinase-positive T-cell lymphoma (ALK+ TCL) cells from apoptosis

Here we report that T-cell lymphomas characterized by the expression of anaplastic lymphoma kinase (ALK+ TCL) fail to express the TNFalpha and frequently display DNA methylation of the TNFalpha gene promoter. While only a subset of the ALK+ TCL-derived cell lines showed a high degree of the promoter methylation, all 6 showed low to nondetectable expression of the TNFalpha mRNA, and none expressed the TNFalpha protein. All 14 ALK+ TCL tissue samples examined displayed some degree of the TNFalpha promoter methylation, which was the most prominent in the distal portion of the the promoter. Treatment with a DNA methyltransferase inhibitor, 5'-aza-2'-deoxy-cytidine (5-ADC), reversed the promoter methylation and led to the expression of TNFalpha mRNA and protein. Furthermore, in vitro DNA methylation of the promoter impaired its transcriptional activity in the luciferase reporter assay. This impairment was seen even if only either distal or proximal portion were methylated, with methylation of the former exerting a more profound inhibitory effect. Notably, the ALK+ TCL cell lines uniformly expressed the type 1 TNFalpha receptor (TNF-R1) protein known to transduce the TNFalpha-induced pro-apoptotic signals. Moreover, exogenous TNFalpha inhibited growth of the ALK+ TCL cell lines in a dose-dependent manner and induced activation of the members of the cell apoptotic pathway: Caspase 8 and caspase 3. These findings provide additional rationale for the therapeutic inhibition of DNA methyltransferases in ALK+ TCL. They also suggest that treatment with TNFalpha may be highly effective in this type of lymphoma.

NFkappaB signaling in carcinogenesis and as a potential molecular target for cancer therapy

It has become increasingly clear that deregulation of the NFkappaB signaling cascade is a common underlying feature of many human ailments including cancers. The past two decades of intensive research on NFkappaB has identified the basic mechanisms that govern the functioning of this pathway but uncovering the details of why this pathway works differently in different cellular contexts or how it interacts with other signaling pathways remains a challenge. A thorough understanding of these processes is needed to design better and more efficient therapeutic approaches to treat complex diseases like cancer. In this review, we summarize the literature documenting the involvement of NFkappaB in cancer, and then focus on the approaches that are being undertaken to develop NFkappaB inhibitors towards treatment of human cancers.

Role of ADAMs in cancer formation and progression

The ADAMs (a disintegrin and metalloproteinase) comprise a family of multidomain transmembrane and secreted proteins. One of their best-established roles is the release of biologically important ligands, such as tumor necrosis factor-alpha, epidermal growth factor, transforming growth factor-alpha, and amphiregulin. Because these ligands have been implicated in the formation and progression of tumors, it might be expected that the specific ADAMs involved in their release would also be involved in malignancy. Consistent with this hypothesis, emerging data from model systems suggest that ADAMs, such as ADAM-9, ADAM-12, ADAM-15, and ADAM-17, are causally involved in tumor formation/progression. In human cancer, specific ADAMs are up-regulated, with levels generally correlating with parameters of tumor progression and poor outcome. In preclinical models, selective ADAM inhibitors against ADAM-10 and ADAM-17 have been shown to synergize with existing therapies in decreasing tumor growth. The ADAMs are thus a new family of potential targets for the treatment of cancer, especially malignancies that are dependent on human epidermal growth factor receptor ligands or tumor necrosis factor-alpha.

Isolated limb perfusion with TNF-alpha and melphalan in locally advanced soft tissue sarcomas of the extremities

Limb-sparing surgery has become all the more important in soft tissue sarcoma (STS) of the extremities since we learned that amputation does not improve survival of these patients. In bulky tumours, however, preoperative strategies to reduce tumour size are then required. Isolated limb perfusion (ILP) with tumour necrosis factor (TNF) has been developed as a biochemotherapeutic therapy to act both on the tumour-associated vasculature and on the tumour itself. It has shown to be a very potent treatment modality, as in early reports response rates were around 80%. Limb salvage could then be achieved in a quite similar percentage. Many confirmatory studies have been performed since, with consistent results even in patients with multiple tumours, after extensive radiotherapy or with metastatic disease, all at the cost of very limited toxicity. This chapter gives an overview of the ILP studies performed in patients with soft tissue limb sarcoma, discusses the mechanism of TNF-mediated vasculotoxic effects on tumour vasculature, and places TNF-based ILP in the multimodality treatment of these patients with extensive STS of the extremities.

TNF-alpha and its inhibitors in cancer

Tumor necrosis factor (TNF)-alpha is implicated in the same time in apoptosis and in cell proliferation. TNF-alpha not only acts as pro-inflammatory cytokine conducing to wide spectrum of human diseases including inflammatory diseases, but can also induce tumor development. The molecular mechanisms of TNF-alpha functions have been intensively investigated. In this review we covered TNF-alpha, the molecule, its signaling pathway, and its therapeutic functions. We provide a particular insight in its paradoxical role in tumor promotion and in its use as anti-tumor agent. This review considers also the recent findings regarding TNF-alpha inhibitors, their pharmacokinetics, and their pharmacodynamics. Six TNF-alpha inhibitors have been considered here: Infliximab, Adalimumab, Golimumab, CDP870, CDP571, Etanercept, and Thalidomide. We discussed the clinical relevance of their functions in treatment of several diseases such as advanced inflammatory rheumatic and bowel disease, with a focus in cancer treatment. Targeting TNF-alpha by these drugs has many side effects like malignancies development, and the long-term sequels are not very well explored. Their efficacy and their safety were discussed, underscoring the necessity of close patients monitoring and of their caution use.

Tumor vasculature-targeted delivery of tumor necrosis factor-alpha

BACKGROUND

Recently, considerable efforts have been directed toward antivascular therapy as a new modality to treat human cancers. However, targeting a therapeutic gene of interest to the tumor vasculature with minimal toxicity to other tissues remains the objective of antivascular gene therapy. Tumor necrosis factor-alpha (TNF-alpha) is a potent antivascular agent but has limited clinical utility because of significant systemic toxicity. At the maximum tolerated doses of systemic TNF-alpha, there is no meaningful antitumor activity. Hence, the objective of this study was to deliver TNF-alpha targeted to tumor vasculature by systemic delivery to examine its antitumor activity.

METHODS

A hybrid adeno-associated virus phage vector (AAVP) was used that targets tumor endothelium to express TNF-alpha (AAVP-TNF-alpha). The activity of AAVP-TNF-alpha was analyzed in various in vitro and in vivo settings using a human melanoma tumor model.

RESULTS

In vitro, AAVP-TNF-alpha infection of human melanoma cells resulted in high levels of TNF-alpha expression. Systemic administration of targeted AAVP-TNF-alpha to melanoma xenografts in mice produced the specific delivery of virus to tumor vasculature. In contrast, the nontargeted vector did not target to tumor vasculature. Targeted AAVP delivery resulted in expression of TNF-alpha, induction of apoptosis in tumor vessels, and significant inhibition of tumor growth. No systemic toxicity to normal organs was observed.

CONCLUSIONS

Targeted AAVP vectors can be used to deliver TNF-alpha specifically to tumor vasculature, potentially reducing its systemic toxicity. Because TNF-alpha is a promising antivascular agent that currently is limited by its toxicity, the current results suggest the potential for clinical translation of this strategy.

Tumor necrosis factor-mediated interactions between inflammatory response and tumor vascular bed

Solid tumor therapy with chemotherapeutics greatly depends on the efficiency with which drugs are delivered to tumor cells. The typical characteristics of the tumor physiology promote but also appose accumulation of blood-borne agents. The leaky tumor vasculature allows easy passage of drugs. However, the disorganized vasculature causes heterogeneous blood flow, and together with the often-elevated interstitial fluid pressure, this state results in poor intratumoral drug levels and failure of treatment. Manipulation of the tumor vasculature could overcome these barriers and promote drug delivery. Targeting the vasculature has several advantages. The endothelial lining is readily accessible and the first to be encountered after systemic injection. Second, endothelial cells tend to be more stable than tumor cells and thus less likely to develop resistance to therapy. Third, targeting the tumor vasculature can have dual effects: (i) manipulation of the vasculature can enhance concomitant chemotherapy, and (ii) subsequent destruction of the vasculature can help to kill the tumor. In particular, tumor necrosis factor alpha is studied. Its action on solid tumors, both directly through tumor cell killing and destruction of the tumor vasculature and indirectly through manipulation of the tumor physiology, is complex. Understanding the mechanism of TNF and agents with comparable action on solid tumors is an important focus to further develop combination immunotherapy strategies.

Nanoparticle enhanced thermal therapies

Thermal therapies such as hyperthermia, radiofrequency ablation, cryoablation, etc. have shown great potential and are gaining increasing clinical acceptance in the treatment of solid tumors. However, these treatment modalities are limited by the size of tumor that can be treated, incomplete tumor kill, and damage to adjacent normal tissues. To address these limitations, the concept of adjuvant-assisted thermal therapies has been proposed and tested to enhance the tumor destructive effects of thermal therapies. CYT-6091, a pegylated colloidal gold nanoparticle containing TNF-alpha bound to its surface, has been extensively investigated in our lab as an adjuvant to enhance thermal therapies. This paper describes our investigations of nanoparticle enhanced thermal therapies in various preclinical and translational models of solid tumors.

The role of TNF in cancer

Tumor necrosis factor (TNF) is an extraordinarily pleiotropic cytokine with a central role in immune homeostasis, inflammation, and host defense. Dependent on the cellular context, it can induce such diverse effects as apoptosis, necrosis, angiogenesis, immune cell activation, differentiation, and cell migration. These processes are of great relevance in tumor immune surveillance, and also play crucial roles in tumor development and tumor progression. It is therefore no surprise that TNF in a context-dependent manner displays pro- and antitumoral effects. Modulation of the activity of the TNF-TNF receptor system thus offers manifold possibilities for cancer therapy. In fact, TNF in combination with melphalan is already an established treatment option in the therapy of advanced soft tissue sarcoma of the extremities and many preclinical data suggest that TNF neutralization could also be exploited to fight cancer or cancer-associated complications.

The tumour microenvironment: a novel target for cancer therapy

Cancer therapy is in the midst of a major paradigm shift. Traditionally, cancer treatments have focused on tumour cells. However, studies over the past few decades have demonstrated that cancer is a vastly complex entity with multiple components affecting a tumour's growth, invasion and metastasis. These components, collectively termed the 'tumour microenvironment', include endothelial cells, pericytes, fibroblasts, inflammatory cells, leucocytes and elements of the extracellular matrix (ECM). Biological agents that target components of the tumour microenvironment may provide an interesting alternative to traditional tumour cell-directed therapy. Because of the complexity of the tumour milieu, the most beneficial therapy will likely involve the combination of one or more agents directed at this new target. This review highlights recent preclinical and clinical studies involving agents that target tumour vasculature, leucocytes, pericytes, cancer-associated fibroblasts and ECM components. We pay particular attention to combination therapies targeting multiple components of the tumour microenvironment, and aim to demonstrate that this strategy holds promise for the future of cancer treatment.

Tumor necrosis factor-alpha-induced accentuation in cryoinjury: mechanisms in vitro and in vivo

Cryosurgical treatment of solid cancer can be greatly assisted by further translation of our finding that a cytokine adjuvant tumor necrosis factor-alpha (TNF-alpha) can achieve complete cancer destruction out to the intraoperatively imaged iceball edge (-0.5 degrees C) over the current clinical recommendation of reaching temperatures lower than -40 degrees C. The present study investigates the cellular and tissue level dose dependency and molecular mechanisms of TNF-alpha-induced enhancement in cryosurgical cancer destruction. Microvascular endothelial MVEC and human prostate cancer LNCaP Pro 5 (LNCaP) cells were frozen as monolayers in the presence of TNF-alpha. Normal skin and LNCaP tumor grown in a nude mouse model were also frozen at different TNF-alpha doses. Molecular mechanisms were investigated by using specific inhibitors to block nuclear factor-kappaB-mediated inflammatory or caspase-mediated apoptosis pathways. The amount of cryoinjury increased in a dose-dependent manner with TNF-alpha both in vitro and in vivo. MVEC were found to be more cryosensitive than LNCaP cells in both the presence and the absence of TNF-alpha. The augmentation in vivo was significantly greater than that in vitro, with complete cell death up to the iceball edge in tumor tissue at local TNF-alpha doses greater than 200 ng. The inhibition assays showed contrasting results with caspase-mediated apoptosis as the dominant mechanism in MVEC in vitro and nuclear factor-kappaB-mediated inflammatory mechanisms within the microvasculatures the dominant mechanism in vivo. These results suggest the involvement of endothelial-mediated injury and inflammation as the critical mechanisms in cryoinjury and the use of vascular-targeting molecules such as TNF-alpha to enhance tumor killing and achieve the clinical goal of complete cell death within an iceball.

Applications of gold nanoparticles in cancer nanotechnology

It has been almost 4 decades since the "war on cancer" was declared. It is now generally believed that personalized medicine is the future for cancer patient management. Possessing unprecedented potential for early detection, accurate diagnosis, and personalized treatment of cancer, nanoparticles have been extensively studied over the last decade. In this review, we will summarize the current state-of-the-art of gold nanoparticles in biomedical applications targeting cancer. Gold nanospheres, nanorods, nanoshells, nanocages, and surface enhanced Raman scattering nanoparticles will be discussed in detail regarding their uses in in vitro assays, ex vivo and in vivo imaging, cancer therapy, and drug delivery. Multifunctionality is the key feature of nanoparticle-based agents. Targeting ligands, imaging labels, therapeutic drugs, and other functionalities can all be integrated to allow for targeted molecular imaging and molecular therapy of cancer. Big strides have been made and many proof-of-principle studies have been successfully performed. The future looks brighter than ever yet many hurdles remain to be conquered. A multifunctional platform based on gold nanoparticles, with multiple receptor targeting, multimodality imaging, and multiple therapeutic entities, holds the promise for a "magic gold bullet" against cancer.

Dysregulation of apoptotic signaling in cancer: molecular mechanisms and therapeutic opportunities

Apoptosis is a tightly regulated cell suicide program that plays an essential role in the maintenance of tissue homeostasis by eliminating unnecessary or harmful cells. Defects in this native defense mechanism promote malignant transformation and frequently confer chemoresistance to transformed cells. Indeed, the evasion of apoptosis has been recognized as a hallmark of cancer. Given that multiple mechanisms function at many levels to orchestrate the regulation of apoptosis, a multitude of opportunities for apoptotic dysregulation are present within the intricate signaling network of cell. Several of the molecular mechanisms by which cancer cells are protected from apoptosis have been elucidated. These advances have facilitated the development of novel apoptosis-inducing agents that have demonstrated single-agent activity against various types of cancers cells and/or sensitized resistant cancer cells to conventional cytotoxic therapies. Herein, we will highlight several of the central modes of apoptotic dysregulation found in cancer. We will also discuss several therapeutic strategies that aim to reestablish the apoptotic response, and thereby eradicate cancer cells, including those that demonstrate resistance to traditional therapies.

Drug selection in isolated hepatic perfusion for nonresectable liver tumors: recent trends and perspectives

Isolated hepatic perfusion (IHP) involves a method of complete vascular isolation of the liver to take the advantage of directed intensive chemotherapy that has minimal systemic toxicity. Recent clinical studies mainly employed melphalan with or without tumor necrosis factor alpha (TNF-α), or with hyperthermia in IHP. The results of these studies showed that higher response rates and survival rates could be achieved by IHP than by traditional therapeutics for non-resectable liver tumors. In this article, we discussed the current status, recent developments and future perspectives of drug selection in IHP.

The European approach to in-transit melanoma lesions

The biological behavior of melanoma is unpredictable. Three to five per cent of melanoma patients will develop in-transit lesions and the median time to recurrence ranges between 13-16 months. At the time of recurrence the risk of occult nodal metastasis, with clinically negative regional lymph nodes, is as high as 50%. The risk of in-transit lesions depends on the tumor biology and not on the surgical approach to the regional lymph nodes. The high incidence of in-transit lesions at the lower limb may be caused by the gravity and delayed lymphatic drainage. The treatment of limited disease is local excision, laser ablation, cryosurgery, while multiple in-transit lesions or bulky disease located in a limb can be successfully treated with regional chemotherapy, a therapeutic isolated limb perfusion or infusion with melphalan or a combination of melphalan and tumor necrosis factor (TNF) alpha. If local regional treatment or systemic dacarbazine based systemic treatment fails, novel systemic treatment strategies with vaccines, antibodies and gene therapy are currently investigated.

Vasculature-targeted tumor necrosis factor-alpha increases the therapeutic index of doxorubicin against prostate cancer

BACKGROUND

Poor penetration and uneven distribution of doxorubicin in tumors limits the efficacy of this drug in patients with prostate cancer (PC). Aim of the study was to investigate whether pre-treatment with NGR-TNF, a tumor necrosis factor-alpha derivative able to target tumor vessels and alter vessel permeability, increases the penetration and the efficacy of doxorubicin in pre-clinical models of PC.

METHODS

Wild type C57BL/6 mice bearing androgen-independent TRAMP-C1 PC and transgenic adenocarcinoma of the mouse prostate (TRAMP) mice, which spontaneously develop PC and metastasis, were treated with repeated cycles of doxorubicin, administered either alone or following NGR-TNF. Tumor growth and drug uptake by cancer cells was evaluated.

RESULTS

Doxorubicin as a single agent blocked the growth of TRAMP-C1 cells in vitro but not in vivo. Pre-treatment of mice bearing subcutaneous TRAMP-C1 tumors with NGR-TNF favored doxorubicin penetration into the tumor mass, and in both TRAMP-C1 and TRAMP models significantly delayed tumor growth without increasing drug-related toxicity.

CONCLUSIONS

Pre-treatment with NGR-TNF significantly expanded the therapeutic index of doxorubicin in mouse models of hormone-dependent and -independent PC.

Synergistic damage of tumor vessels with ultra low-dose endothelial-monocyte activating polypeptide-II and neovasculature-targeted tumor necrosis factor-alpha

High-dose endothelial-monocyte activating polypeptide II (EMAP-II), a tumor-derived antiangiogenic cytokine, can sensitize tumor vasculature to the damaging activity of high-dose tumor necrosis factor (TNF)-alpha. However, this combination cannot be used for systemic treatment of patients because of prohibitive toxicity. We have found that this limitation can be overcome by combining a TNF-targeting strategy with the use of ultra low-dose EMAP-II. Coadministration of 0.1 ng of EMAP-II and 0.1 ng of CNGRCG-TNF (NGR-TNF), a peptide-TNF conjugate able to target tumor blood vessels, inhibited lymphoma and melanoma growth in mice, with no evidence of toxicity. This drug combination induced endothelial cell apoptosis in vivo and, at later time points, caused reduction of vessel density and massive apoptosis of tumor cells. Ligand-directed targeting of TNF was critical because the combination of nontargeted TNF with EMAP-II was inactive in these murine models. The synergism was progressively lost when the dose of EMAP-II was increased in the nanogram to microgram range, supporting the concept that the use of low-dose EMAP-II is critical. Studies on the mechanism of this paradoxical behavior showed that EMAP-II doses >1 ng induce the release of soluble TNF receptor 1 in circulation, a strong counter-regulatory inhibitor of TNF. Tumor vascular targeting with extremely low amounts of these cytokines may represent a new strategy for cancer treatment.

Convergence of genetic, nutritional and inflammatory factors in gastrointestinal cancers

Gastrointestinal cancers account for 20% of all cancer incidences worldwide. Colorectal cancer is the second most common cause of all cancer-related mortality and is increasing in Western societies. Infection and inflammation contribute to 15-20% of all malignancies, and are predisposing risk factors for gastrointestinal cancers. Helicobacter pylori infection is commonly associated with gastric cancers, and chronic inflammation increases the risk of colorectal cancer by 1% per year. Micronutrient status and common genetic variations in human populations modify risk for gastrointestinal cancer. Chronic inflammation promotes carcinogenesis by inducing gene mutations, inhibiting apoptosis, and stimulating angiogenesis and cell proliferation. Inflammation also induces epigenetic alterations that are associated with cancer development. Two key genes in the inflammatory process, cyclooxygenase-2 (COX-2) and nuclear factor-kappa B (NF-kappaB), provide a mechanistic link between inflammation and cancer and are targets for chemoprevention. Dietary components, and human genetic variation that affects nutrient utilization, can directly modify inflammatory processes and/or suppress genomic alterations that are the molecular antecedents of cancers. The present report focuses on the convergence of genetic, nutritional, and inflammatory factors in the initiation and progression of gastrointestinal cancers, and the emerging dietary strategies for cancer prevention.

Death receptor expression is associated with poor response to chemotherapy and shorter survival in metastatic ovarian carcinoma

BACKGROUND

Death receptors mediate both apoptosis and survival in cancer cells. The authors analyzed death receptor expression in metastatic ovarian carcinoma.

METHODS

Viable tumor cells in ovarian carcinoma effusions (n = 95) were analyzed for DR4, DR5, Fas, TNFR1, and TNFR2 expression using flow cytometry. Results were analyzed for association with clinicopathologic parameters, chemotherapy response, and survival.

RESULTS

DR4, DR5, and Fas were expressed by the majority of specimens, with less frequent expression of TNFR1 and TNFR2. DR4 (P = .005) and TNFR2 (P = .041) expression was higher in FIGO stage IV compared with stage III tumors. Effusions from patients who responded poorly to chemotherapy administered at disease recurrence had significantly higher DR4 (P = .006), DR5 (P = .01), and Fas (P = .001) expression. In univariate survival analysis, higher DR4 expression in viable cells correlated with poor overall (P = .0352) and progression-free (P = .0411) survival. DR4 expression was found to be an independent predictor of overall (P = .008) and progression-free (P = .003) survival.

CONCLUSIONS

The authors have presented the first evidence of death receptor coexpression in ovarian carcinoma effusions. The association of death receptor expression in effusions with advanced stage, poor response to chemotherapy, and shorter survival suggests that these molecules are linked to an aggressive clinical course in metastatic ovarian carcinoma.

HDAC2 deficiency sensitizes colon cancer cells to TNFalpha-induced apoptosis through inhibition of NF-kappaB activity

HDAC inhibitors exert potent anti-tumorigenic and anti-inflammatory activity. Their effects are selective for transformed cells, and we recently demonstrated that transformation of epithelial cells with k-Ras sensitizes cells to HDACi induced apoptosis. The aim of this study was to determine whether the ability of HDACi to modulate signaling by a major pro-inflammatory cytokine, TNFalpha, is also restricted to cells that harbor mutant k-Ras. We used the system of two isogenic cell lines that differ by the presence of mutant k-Ras, HCT116 and Hke3 cells. Treatment of cells with TNFalpha alone did not induce apoptosis; however HDACi potentiated TNFalpha-induced apoptosis in both HCT116 and Hke3 cells. Thus, the ability of HDACi to sensitize cells to TNFalpha-induced apoptosis appears to be k-Ras independent. We demonstrated that HDACi inhibited TNFalpha-induced NF-kappaB transcriptional and DNA binding activity in both cell lines, underlying the increased apoptosis in cells treated with both agents. We showed that overexpression of HDAC2 enhanced TNFalpha-induced NF-kappaB activity and that silencing of HDAC2 decreased NF-kappaB activity. Finally, silencing of HDAC2 expression was sufficient to sensitize colon cancer cells to TNFalpha-induced apoptosis. The ability of HDACi to interfere with NF-kappaB activity is likely to contribute to their potent anti-tumorigenic and anti-inflammatory activity.

5-lipoxygenase suppresses TNF-α-induced apoptosis in pancreatic tumor cell lines

AIM: To investigate the effects of 5-lipoxygenase and LTB4 on the proliferation and apoptosis of pancreatic cancer cells in vitro.

METHODS: The human pancreatic cancer cell lines ASPC-1, PANC-1 and SW1990 were cultured and the levels of 5-LOX and the supernatant product LTB4 were examined by Western blot and ELISA. TNF-α-induced cell apoptosis was analyzed by annexin V/PI double staining with flow cytometry. 5-LOX cDNA stably transfected SW1990 cell lines were established and treated with TNF-α. Their sensitivity to apoptosis induction was examined.

RESULTS: The pancreatic cell lines tested in this study all expressed substitute levels of 5-LOX and LTB4. The percentages of apoptotic wild-type SW1990 cells were 25.4% ± 3.65% and 43.5% ± 5.23% after 12 h and 24 h treatment with 20 μg/L TNF-α, respectively. However, these effects were significantly decreased (P < 0.01) in 5-LOX over-expressing cells. The percentages of these cells undergoing apoptosis were 13.2% ± 2.01% and 21.7% ± 3.65% after 12 h and 24 h treatment, respectively. Furthermore, the addition of exogenous LTB4 (10 nmol/L) significantly suppressed the percentage of wild-type cells undergoing apoptosis from 47.6% ± 5.32% to 18.5% ± 5.69%. Blocking LTB4 signals with specific receptor antagonists reversed the sensitivity of 5-LOX transfected cells to apoptosis.

CONCLUSION: High levels of expression of 5-LOX and LTB4 make pancreatic cell lines more resistant to TNF-α-induced apoptosis, suggesting that the 5-LOX pathway plays an important role in the pathogenesis of pancreatic cancer.

Heme oxygenase-1 in tumors: is it a false friend?

Heme oxygenase-1 (HO-1) catalyzes the oxidation of heme to biologically active products: carbon monoxide (CO), biliverdin, and ferrous iron. It participates in maintaining cellular homeostasis and plays an important protective role in the tissues by reducing oxidative injury, attenuating the inflammatory response, inhibiting cell apoptosis, and regulating cell proliferation. HO-1 is also an important proangiogenic mediator. Most studies have focused on the role of HO-1 in cardiovascular diseases, in which its significant, beneficial activity is well recognized. A growing body of evidence indicates, however, that HO-1 activation may play a role in carcinogenesis and can potently influence the growth and metastasis of tumors. HO-1 is very often upregulated in tumor tissues, and its expression is further increased in response to therapies. Although the exact effect can be tissue specific, HO-1 can be regarded as an enzyme facilitating tumor progression. Accordingly, inhibition of HO-1 can be suggested as a potential therapeutic approach sensitizing tumors to radiation, chemotherapy, or photodynamic therapy.

Mast cells in vulnerable atherosclerotic plaques--a view to a kill

The aim of the present review is to discuss the participation of mast cells in the pathogenesis of erosion and rupture of atherosclerotic plaques, the major causes behind acute coronary syndromes and myocardial infarction. We present ex vivo observations describing mast cells and their activation in human atherosclerotic plaques and discuss in vitro and in vivo data showing that mast cells are potential regulators of inflammation, immunity and adverse remodeling, including matrix remodeling and cell death. Furthermore, we focus on studies that have been performed with human tissues and human mast cells, but when appropriate, we also discuss observations made in animal models. Finally, we present potential pharmacological means to modulate mast cell responses in the arterial vessel walls.

TNF-alpha-based accentuation in cryoinjury--dose, delivery, and response

Cryosurgery is a minimally invasive cancer treatment using cryogenic temperatures. Intraoperative monitoring of iceball growth is an advantage of the treatment. However, whereas the iceball can be easily visualized, destruction within the iceball is incomplete and the means to monitor the "kill zone" are urgently needed. Recently, we have shown the ability of tumor necrosis factor-alpha (TNF-alpha) to enhance destruction within an iceball. To avoid systemic toxicity, we delivered TNF-alpha selectively to the tumor by a gold nanoparticle of 30-nm diameter (CYT-6091) tagged with TNF-alpha and thiol-derivatized polyethylene glycol. Using a dorsal skin fold chamber (DSFC) in a nude mouse, both normal skin and human prostate carcinoma (LNCaP Pro 5) were pretreated with soluble TNF-alpha (topically or i.v.) or CYT-6091 (i.v.) and frozen after 4 h. The cryolesion was assessed after 3 days by comparing histologic necrosis with perfusion defects. Hind limb tumors were also treated by visibly encompassing the tumor with an iceball and assessing gross changes over time. A 5-mug dose of soluble TNF-alpha or CYT-6091 increased the temperature threshold of necrosis in the tumor in the DSFC from -14.0 +/- 1.6 degrees C (n = 6) to 0.9 +/- 1.5 degrees C (n = 6) and -1.5 +/- 3.7 degrees C (n = 6), respectively. In hind limb tumors, the same dose resulted in significant tumor shrinkage and remission in 2 of 8 (for soluble TNF-alpha) and in 3 of 8 (for CYT-6091). The nanoparticle alone group without TNF-alpha increased the temperature threshold of necrosis to -7.0 +/- 2.3 degrees C in the tumor in the DSFC and more shrinkage of the tumor in the hind limb when compared with cryo alone treatment. Systemic toxicity was noted in all soluble TNF-alpha groups but none with CYT-6091. These results suggest that it is possible to destroy all of a tumor within an iceball by preincubation with TNF-alpha and systemic toxicity can be avoided by CYT-6091.

Early experience with novel immunomodulators for cancer treatment

Immunotherapy involves the treatment of cancer by modification of the host-tumour relationship. It is now known that this relationship is quite complex and only some of the interactions have been elucidated. Early attempts at immunotherapy, such as Coley's toxins, were undertaken without an understanding of the processes mediating the effects. With a better understanding of the immunology of this anticancer response, recent trials have focussed on certain aspects of the process to stimulate an antitumour response. In this review, the authors discuss a number of novel biological response modifiers that work as general stimulants of the immune system, through varied mechanisms including induction of stimulatory cytokines (such as IFN-alpha, TNF-alpha and IL-12) and activation of T cells and the antigen-presenting dendritic cells. These compounds include Toll-like receptor agonists, several of which are in clinical trials at present. In addition to immunomodulatory activity, some compounds such as 5,6-dimethylxanthenone-4-acetic acid (DMXAA) and thalidomide and its analogues also target existing or developing tumour vasculature. Some of these compounds have single-agent activity in clinical trials, while others such as DMXAA have shown promise in combination with chemotherapy without increasing toxicity. Lactoferrin is another compound that has shown clinical activity with low toxicity. At present, accepted indications for immunotherapy are limited to a few cancers such as renal cell carcinoma and melanoma. This paper looks at some of the reasons for the limited impact of immunotherapy so far and suggest possible avenues for further research with a greater likelihood of success.

Involvement of immune response in anti-tumor effects of Staphylococcus aureus filtrate preparation

PURPOSE

Staphylococcus Aureus Filtrate Preparation (SAFP) is a preparation of low-virulence strain of Staphylococcus aureus. In our study, we aimed to determine the anti-tumor activity of SAFP in vivo and explore the potential mechanism.

METHODS

Our study evaluated the anti-tumor activity of SAFP in four cancer cell models in vivo and determined its up-regulatory effects on mice immune system in vivo.

RESULTS

It showed that 7.2 ng/10 g SAFP could inhibit the progression of murine hepatoma H22 and sarcoma S180, and the tumor inhibition rates achieved 48.1 and 35.7%, respectively. In human non-small cell lung cancer A549 and hepatoma BEL7402 xenograft athymic mice models, T/C of 7.2 ng/10 g SAFP group reached 41.0% in A549 model and 21.0% in BEL7402 model. Meanwhile, SAFP also significantly increased the proliferation of cultured mice splenocytes to 162.1%, and 7.2 ng/kg SAFP significantly (P < 0.001) raised the activity of NK cells, elevated the serum level of IL-2, TNF-alpha and IFN-gamma in mice.

CONCLUSION

SAFP exhibited high efficiency in inhibiting the growth of cancer cells in a dose-dependent manner, which possibly attributed to its regulatory effects of immune system.